Pyrotechnic devices

ABSTRACT

A signal device comprising a rocket housed in a discharge tube having a closure at its upper end and a closure displacing device including an actuating member in the region of the lower end of the discharge tube, the actuating member being operable to ignite the rocket after displacement of the closure.

Unite ties Elstow et al.

[451 May 29, 1973 PYROTECHNIC DEVICES Inventors: William Rupert Brooke Elstow, Laverstock; Anthony Ronald Witt, Amesbury, both of England Pains-Wessex Limited, Salisbury, Wiltshire, England Filed: Apr. 22, 1970 Appl. No.: 30,784

Assignee:

U.S. Cl ..l02/34.1, 102/356 Int. Cl. ..C06d 1/04 Field of Search 102/34.1-34.5, 35, 35.6, 39

References Cited UNITED STATES PATENTS 1/1941 Holm et a1 ..l02/39 4/1950 Hickman 102/34.4 8/1950 Dwyer et a1. l02/35.6 X 3/1957 Clauser et al l02/34.4 X 10/1963 Aberg ..102/34.4

Primary ExaminerRobert F. Stahl Attorney-Hall & Houghton ABSTRACT A signal device comprising a rocket housed in a discharge tube having a closure at its upper end and a closure displacing device including an actuating member in the region of the lower end of the discharge tube, the actuating member being operable to ignite the rocket after displacement of the closure.

10 Claims, 2 Drawing Figures PAIENTED HAYZQIQTS (35,706

SHEET 2 BF 2 PYROTECHNIC DEVICES A signal device comprising a rocket housed in a discharge tube having a closure at its upper end and a closure displacing device including an actuating member in the region of the lower end of the discharge tube, the actuating member being operable to ignite the rocket after displacement of the closure.

This invention relates to signal rocket devices, and especially to signal rocket devices suitable for being fired from the hand.

The invention provides a signal device comprising a signal rocket housed in a discharge tube, means for igniting the rocket, closure means at the upper end of the discharge tube, and mechanical means for displacing the closure means, the mechanical displacing means including a member that is situated at or close to the lower end of the discharge tube and is coupled to the igniting means, the arrangement being such that the member is movable to effect displacement of the closure means and to operate the igniting means to ignite the rocket after displacement of the closure means.

The removal of the closure means at the upper end of the discharge tube before ignition of the rocket gives improved directional accuracy as compared with allowing the closure means to be displaced by the rocket itself as it leaves the discharge tube and, in the device of the invention, this is achieved without the operator having to do more than move the member that serves to ignite the rocket.

Advantageously, the arrangement is such that one movement of the said member, preferably a rotation about the axis of the rocket, serves both to displace the closure means at the upper end of the discharge tube and to release the member from engagement, preferably, a screw-threaded engagement, with the discharge tube and, thereafter, movement of the said member away from the discharge tube serves to operate the igniting means. This arrangement provides a simple way of ensuring that the rocket is ignited after the closure means at the upper end of the discharge tube has been displaced.

Advantageously, the mechanical displacing means comprises means for imparting upward axial movement to a displacing member to effect displacement of the closure means. The displacing member may be a hollow cylinder surrounding the rocket in the discharge tube but which is preferably the rocket itself. The means for imparting upward axial movement to the displacing member may comprise cam means, preferably, (when a rotation of the member serves to displace the closure means and to release the member from engagement with the discharge tube) rotary cam means with the axis of rotation coincident with the axis of the discharge tube. Preferably, the cam means is positioned in the lower end portion of the discharge tube.

The said member may be arranged to extend into the lower end of the discharge tube and engage directly with the cam means or cam follower means, such that rotation of the member causes the required rotation of the cam means or cam follower means. For example, the member may be formed with a pair of opposed axially-extending projections which engage the cam means or cam follower means.

Preferably, the cam means comprises a cam member formed with two circumferentially-extending inclined surfaces.

Advantageously, the discharge tube is closed at its lower end and the arrangement is such that movement of the said member to displace the said closure means and ignite the rocket causes a vent to be formed (other than at the upper end of the discharge tube) through which exhaust gases from the rocket in the discharge tube can reach the atmosphere. This arrangement enables the signal device to be sealed prior to use while ensuring that the rocket leaves the discharge tube substantially solely as a result of the momentum of its exhaust gases, thereby reducing or eliminating recoil and improving the stability of the rocket as it leaves the discharge tube, as compared with its being ejected, at least in part, by the build-up of pressure in the discharge tube. When the vent is formed, since its formation is effected by movement of the same member as is used to displace the closure means at the upper end of the discharge tube and to ignite the rocket, the simplicity of operation of the rocket is not impaired. For example, if the rocket is fired from the hand, the discharge tube can be held in one hand, and the rocket operated solely by movement of the said member by the other hand, the operation being carried out without the user having to change his grip. This is of particular advantage if the rocket is used by a person floating in the sea, and the fact that the rocket can be sealed prior to use and fires with little or no recoil are further advantages in such a case.

The vent to the atmosphere for the exhaust gases from the rocket may comprise holes in the lower portion of the discharge tube, or holes in a closure member for the lower end of the discharge tube, the arrangement being such that the holes are uncovered by movement of the said member. Preferably, however, the said member itself forms at least a part of means for closing the lower end of the discharge tube and the arrangement is such that ignition of the rocket cannot take place until the said member has been removed from the tube. This arrangement ensures that the rocket is not ignited before a vent for its exhaust gases has been formed in the discharge tube.

Preferably, a delay mechanism, for example, a fuse, is incorporated in the igniting mechanism. This gives the user of the rocket time to hold the discharge tube with both hands before the rocket is discharged.

The ignition means of the rocket may be formed as part of the rocket, but it is preferably arranged to remain in the discharge tube after the rocket has been fired. Thus, the ignition means may be housed in the lower part of the discharge tube.

A signal device, constructed in accordance with the invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which,

FIG. 1 is an axial cross-section of the device; and

FIG. 2 is an exploded perspective view of the device.

Referring to FIG. 1, the device, which is a signal flare device, comprises a generally tubular rocket, indicated generally by the reference numeral 1, slidably housed in a discharge tube 2, which tube is closed at its upper end by a closure 2a sealed in position.

The rocket 1 comprises a generally tubular casing 3, which houses the flare composition 4 in its upper part, the rocket propellant 5 in its central part and means for igniting the propellant, indicated generally by the reference numeral 6, in its lower part. The lower part of the rocket casing 3 is formed with three rectangular ports equally spaced around the circumference of the rocket (not shown) to assist in stabilizing the flight of the rocket.

The flare composition 4 is contained in a tubular casing of pressed paper 7, which is slidable in the rocket casing 3. A layer of igniting composition 8 for the flare composition 4 is formed in the lower part of the tubular casing 7, which is partially closed at its lower end by an annular paper disc 9. The upper end of the tubular casing 7 is closed by a mill-board disc 10. Contained in the uppermost portion of the rocket casing 3, between the mill-board disc 10 and the top of the rocket casing, which is closed by a cap 1 l, is a parachute K2, the cords 13 of which are stapled to the mill-board disc 10. A paPer washer l4 separates the mill-board disc 10 from the parachute 12.

The propellant 5 is contained in a cylindrical casing 15 which is located against axial movement in the rocket casing 3 by two waists 16 formed in the rocket casing. The upper end of the cylindrical casing 15 is formed with a short, hollow neck portion l7 of which the upper end abuts the paper disc 9, and the neck portion is filled with a slow-burning pyrotechnic composition 18 which transmits combustion from the propel lant 5 to the flare-igniting composition 8. The bottom edge of the cylindrical casing 15 is turned inwardly to form a lip which supports a convergent-divergent nozzle member 19, the nozzle member being located against upward movement relative to the casing 15 by a waist 2f formed in the casing.

The upper surface of the nozzle member 113 is formed with a circular groove containing priming material 21, which serves to aid ignition of the propellant 5 when a propellant igniter 22 combusts. The propellant igniter 22, the part of which below the nozzle member 39 is sleeved, is connected to a fuse 23, which imparts a delay to the ignition of the propellant 5 and which is supported in a ferrule 24, the ferrule itself being supported in a generally tubular casing 25. The casing 25 serves to house the rocket striker mechanism, indicated generally by the reference numeral 26, and a centerfire percussion cap 27 which is situated immediately below the open end of the ferrule 24.

The rocket striker mechanism 26 comprises a polypropylene tube 23 which is held in position in the tubular casing 25 by means of a pin (not shown) which passes through the tubular casing 25, and a springloaded plunger indicated generally by the reference numeral 3f). The head 3i of the plunger 30, which is formed with a firing pin 32 for striking the percussion cap 27 is integral with the shaft 33 of the plunger, both the head and the shaft being made of brass.

Towards the lower end of the shaft 33, a circumferential groove 34 is formed in the shaft which lies, when the plunger 30 is in its unretracted position, in a part 35 of the tube 28 of reduced internal diameter. The lower end portion 36 of the shaft 33 is contained in a socket in a member 37, which member is split, in the plane of the section, into two similar parts. The upper end portion of the member 37 is externally cylindrical and has a diameter slightly less than that of the narrower part 35 of the tube 28 so that, when the plunger 30 is in unretracted position, the parts of the member 37 are held in engagement with the groove 34 in the plunger, but, when the member 37 is pulled downwarclly, clear of the narrower part 35 of the tube 27, the two parts of the member 37 separate to release the plunger which then strikes the cap 27 under the action of a coil spring 38. The spring 38 acts in compression between the head 31 of the plunger and the shoulder formed by the reduction in the internal diameter of the tube 23. The narrow part 35 of the tube 28 is formed internally with axially-extending runners which facilitate smooth withdrawal of the member 37 from the tube. The lower end of the member 37, which is enlarged to prevent it from entering the narrow part 35 of the tube 28, is connected by a lanyard 39 to closure means for the lower end of the discharge tube 2, which is in the form of a plug indicated generally by the reference numeral 40.

The tubular casing 25 is formed on the outside with two integral alignment fins (not shown), which extend in opposite radial directions at right angles to the plane of the section and of which the outer ends make a sliding fit within the rocket casing 3. Below the alignment fins, the tubular casing 25 is formed with two integral fins indicated generally by the reference numeral 41 extending in opposite radial directions in the plane of the section.

The outer part 42 of each of the fins 41 forms a cam follower of which the lower surface runs on one of two similar rotary cam surfaces formed at the top of a collar 43. The upper surfaces of the cam followers 42 bear against the lower end of a polypropylene ring 44 the outer portion of the upper surface of which bears against the lower end of the rocket casing 3 so that the ring serves to distribute the thrust from the cam followers evenly around the circumference of the rocket casing. The collar 43 is located axially in the bottom end portion of the discharge tube 2 between the turned-in end portions of the wall of the discharge tube and a waist 45 formed in the wall of the discharge tube. Further, the under surface of the collar 43 and the upper surface of the inwardly-turned end portion of the wall of the discharge tube 2 are each serrated to prevent relative rotation between the collar and the discharge tube.

The plug &0, the collar 41-3 with its rotary cam surfaces, the cam follower portions 42 of the fins 41 and the ring form, as will be apparent from the following description, part of a device for the mechanical displacement of the closure 2a, and the plug 40 forms an actuating member for the closure displacing device.

The cam surfaces, the lowest parts of which are shown in HO. 1 of the drawings, each extend around half the circumference of the collar 43, and the height of each cam surface from the collar varies smoothly along its length from zero at one end to full height at the other end. The angle of inclination of each cam surface varies in a circumferential direction so that, starting from the lowest position on the cam, a rotation of the associated cam follower 42 through imparts to the cam follower a lift of only one third of the total lift imparted when the cam follower is rotated through the maximum angle of When the device is assembled ready for use, care is taken to ensure that the cam followers 42 are situated at the lowest parts of the respective cam surfaces.

The collar 43 is internally screw-threaded for engagement with the actuating member 40, of which the upper portion is externally screw-threaded and a sealing member, which may be in the form of an O-ring 46 or in the form of a flat washer, that is interposed between the closure means and the lower end of the discharge tube 2 serves to seal that end of the discharge tube. The screw-threads on the collar 43 and on the actuating member 40 together form rotary releasable engagement means for releasably engaging the actuating member 40 and the discharge tube 2. The release of the actuating member 40 from engagement with the discharge tube 2 is accomplished by unscrewing it from the discharge tube 2.

The actuating member 40 is formed with a central hollow recess into which fits a hollow cylindrical extension member 47, the inner wall of the recess and the outer wall of the cylindrical member in contact with it being formed with axial splines to prevent relative rotation between the actuating member 40 and the cylindrical extension member 47. The cylindrical member 47 is secured to the actuating member 40 by a screw 48 which is received by a central bore 49 formed in the cylindrical member, and the tapered lower end portion of the cylindrical member forms a water-tight seal with the actuating member 40. The cylindrical member 47 precaution against the entry of water, a washer may be interposed between the cylindrical member 47 The upper part of the cylindrical member 47 is formed with two diametrically opposite radially extending slots into which the fins 42 are received, so that the casing 25 can be rotated by rotation of the actuating member 40, the depth of the slots being sufficient to ensure that the fins remain in engagement with the actuating member 40 as the latter is unscrewed.

In operation, the rocket is held in one hand and the actuating member 40 unscrewed with the other, thereby rotating the fins 42 on the tubular casing 25. The sense of the screw-thread on the actuating member 40 and the direction of inclination of the cam surfaces is such that the unscrewing of the actuating member causes the cam followers 42 to move along the cam surfaces in the direction of increasing height. The cam followers 42 have moved through an angle of 90 in FIG. 2 from the position shown in FIG. 1. The resulting thrust applied to the rocket 1 through the ring 44 causes the rocket to be advanced along the discharge tube 2 and in turn to displace the closure 2a at the top of the discharge tube. Further unscrewing of the actuating member 40 releases it from the discharge tube 2 and movement of the actuating member away from the discharge tube, imparting a tension to the lanyard 39, causes the rocket striker mechanism 26 to be operated in the manner described hereinbefore and the rocket 1 to be ignited. The removal of the actuating member 40 provides a vent at the lower end of the discharge tube 2, and the rocket leaves the discharge tube substantially solely as a result of the momentum of its exhaust gases. The ignition means 6 remains in the discharge tube 2.

When the rocket propellant 5 has burned out, the flare-igniting composition 8 is ignited by the slowburning pyrotechnic composition 18, and the tubular casing 7, which is attached to the parachute 12 and which contains the flare composition 4 is ejected from the rocket casing 3. The flare casing 7 containing the burning flare composition 4 then falls under the control of the parachute 12.

We claim:

1. A signal device which comprises a discharge tube, a rocket housed in said discharge tube, rocket igniting means, a closure at the upper end of said discharge tube, and a mechanical closure displacing device, said closure displacing device including a movable actuating member situated in the region of the lower end of said discharge tube, and means coupling said actuating member to said igniting means for enabling it to operate said igniting means after displacement of said closure.

2. A signal device according to claim 1, which includes releasable engagement means for engaging said 7 actuating member with said discharge tube, said closure displacing device being operable to cause displacement of said closure in response to release of said engagement means, and igniting means responsive to movement of said actuating member away from said discharge tube to permit actuation of said igniting means after release of said engagement means.

3. A signal device according to claim 2, wherein said releasable engagement means comprises relatively rotatable members released by relative rotation thereof.

4. A signal device according to claim 3, wherein one of said relatively rotatable members is screw threaded to the other and releasable by unscrewing the same therefrom.

5. A signal device according to claim 1, wherein said closure displacing device includes means for advancing said rocket to thereby displace said closure.

6. A signal device according to claim 5, wherein said rocket advancing means includes cam means.

7. A signal device according to claim 6, wherein the rocket advancing means includes rotary cam means with the axis of rotation coincident with the axis of the discharge tube, and the actuating member is rotatable about the axis of the discharge tube to thereby cause said rocket to displace said closure under the action of said cam means.

8. A signal device according to claim 7, wherein the rotary cam means has two circumferentially-extending cam surfaces, the lowest part of each surface being level with each other, and the heights of the cam surfaces in the direction of the axis of the discharge tube gradually increasing at.the same rate as each other in the same direction around the axis of the discharge tube.

9. A signal device according to claim 1, wherein said igniting means is separate from said rocket thereby to remain in said discharge tube after said rocket has been fired.

10. A signal device according to claim 1, wherein said lower end of said discharge tube is open, said actuating member forms a releasable closure for said opening, and said coupling means permits actuation of said igniting means only after the release of said actuating member from said discharge tube has taken place and a vent has thereby been formed.

* l t t l 

1. A signal device which comprises a discharge tube, a rocket housed in said discharge tube, rocket igniting means, a closure at the upper end of said discharge tube, and a mechanical closure displacing device, said closure displacing device including a movable actuating member situated in the region of the lower end of said discharge tube, and means coupling said actuating member to said igniting means for enabling it to operate said igniting means after displacement of said closure.
 2. A signal device according to claim 1, which includes releasable engagement means for engaging said actuating member with said discharge tube, said closure displacing device being operable to cause displacement of said closure in response to release of said engagement means, and igniting means responsive to movement of said actuating member away from said discharge tube to permit actuation of said igniting means after release of said engagement means.
 3. A signal device according to claim 2, wherein said releasable engagement means comprises relatively rotatable members released by relative rotation thereof.
 4. A signal device according to claim 3, wherein one of said relatively rotatable members is screw threaded to the other and releasable by unscrewing the same therefrom.
 5. A signal device according to claim 1, wherein said closure displacing device includes means for advancing said rocket to thereby displace said closure.
 6. A signal device according to claim 5, wherein said rocket advancing means includes cam means.
 7. A signal device according to claim 6, wherein the rocket advancing means includes rotary cam means with the axis of rotation coincident with the axis of the discharge tube, and the actuating member is rotatable about the axis of the discharge tube to thereby cause said rocket to displace said closure under the action of said cam means.
 8. A signal device according to claim 7, wherein the rotary cam means has two circumferentially-extending cam surfaces, the lowest part of each surface being level with each other, and the heights of the cam surfaces in the direction of the axis of the discharge tube gradually increasing at the same rate as each other in the same direction around the axis of the discharge tube.
 9. A signal device according to claim 1, wherein said igniting means is separate from said rocket thereby to remain in said discharge tube after said rocket hAs been fired.
 10. A signal device according to claim 1, wherein said lower end of said discharge tube is open, said actuating member forms a releasable closure for said opening, and said coupling means permits actuation of said igniting means only after the release of said actuating member from said discharge tube has taken place and a vent has thereby been formed. 